Implement accounts api & update to new core

[Jikstra]

Missing (bindings)

• [x] dc_accounts_all_work_done
• [x] dc_accounts_start_io
• [x] dc_accounts_stop_io
• [x] dc_accounts_maybe_network
• [x] dc_accounts_maybe_network_lost
• [x] dc_accounts_get_event_emitter

Missing (high level api)

• [x] All

Todo

• [x] fix tests
• [x] fix seg fault

Remove

• [x] dc_create_chat_by_msg_id
• [x] dc_decide_on_contact_request
• [x] dc_marknoticed_contact
• [x] dc_msg_get_real_chat_id

[Jikstra]

Currently i'm fighting a seg fault:

Using host libthread_db library "/usr/lib/libthread_db.so.1".
[New Thread 0x7ffff7a29640 (LWP 282750)]
[New Thread 0x7ffff7228640 (LWP 282751)]
[New Thread 0x7ffff6a27640 (LWP 282752)]
[New Thread 0x7ffff6226640 (LWP 282753)]
[New Thread 0x7ffff5a25640 (LWP 282754)]
[New Thread 0x7ffff7fc6640 (LWP 282755)]
[Detaching after fork from child process 282756]

  static tests
    ✓ reverse lookup of events
    ✓ event constants are consistent
    1) static method maybeValidAddr()
    2) static getSystemInfo()

Thread 1 "node" received signal SIGSEGV, Segmentation fault.
0x00007ffff7a6c01b in kill () from /usr/lib/libc.so.6
(gdb) backtrace
#0  0x00007ffff7a6c01b in kill () from /usr/lib/libc.so.6
#1  0x00000000013aae49 in uv_kill (pid=<optimized out>, signum=<optimized out>) at ../deps/uv/src/unix/process.c:521
#2  0x0000000000a9c293 in node::Kill(v8::FunctionCallbackInfo<v8::Value> const&) ()
#3  0x0000000000c06acb in v8::internal::MaybeHandle<v8::internal::Object> v8::internal::(anonymous namespace)::HandleApiCallHelper<false>(v8::internal::Isolate*, v8::internal::Handle<v8::internal::HeapObject>, v8::internal::Handle<v8::internal::HeapObject>, v8::internal::Handle<v8::internal::FunctionTemplateInfo>, v8::internal::Handle<v8::internal::Object>, v8::internal::BuiltinArguments) ()
#4  0x0000000000c08076 in v8::internal::Builtin_Impl_HandleApiCall(v8::internal::BuiltinArguments, v8::internal::Isolate*) ()
#5  0x0000000000c086f6 in v8::internal::Builtin_HandleApiCall(int, unsigned long*, v8::internal::Isolate*) ()
#6  0x0000000001427159 in Builtins_CEntry_Return1_DontSaveFPRegs_ArgvOnStack_BuiltinExit ()
#7  0x00000000013bfee2 in Builtins_InterpreterEntryTrampoline ()
#8  0x0000264fb96c0471 in ?? ()
#9  0x00002a57b4fc3c99 in ?? ()
#10 0x0000000700000000 in ?? ()
#11 0x0000264fb96c0541 in ?? ()
#12 0x0000000b00000000 in ?? ()
#13 0x0004507a00000000 in ?? ()
#14 0x0000065761a81e79 in ?? ()
#15 0x0000000b00000000 in ?? ()
#16 0x0000264fb96c0471 in ?? ()
#17 0x0000065761a81e79 in ?? ()
#18 0x00002a57b4fc3c99 in ?? ()
#19 0x0000264fb96c0471 in ?? ()
#20 0x000000af00000000 in ?? ()
#21 0x00003502adfb9fb1 in ?? ()
#22 0x00002eb21b465b31 in ?? ()
#23 0x00002eb21b4713c1 in ?? ()
#24 0x00007fffffffd618 in ?? ()
#25 0x00000000013bfee2 in Builtins_InterpreterEntryTrampoline ()
#26 0x000006553fba6f99 in ?? ()
#27 0x0004507a00000000 in ?? ()
#28 0x0000065761a81e79 in ?? ()
#29 0x000006553fba6f99 in ?? ()
#30 0x0004507a00000000 in ?? ()
#31 0x0000065761a81e79 in ?? ()
#32 0x00002eb21b465b31 in ?? ()
#33 0x0000005300000000 in ?? ()
#34 0x00003502adfb9e39 in ?? ()
#35 0x000006553fba7021 in ?? ()
#36 0x000006553fba6ff1 in ?? ()
#37 0x00007fffffffd650 in ?? ()
#38 0x00000000013b9e19 in Builtins_ArgumentsAdaptorTrampoline ()
#39 0x0000065761a81e79 in ?? ()
#40 0x0000000000000000 in ?? ()